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The Air Quality System (AQS) is EPA's repository of ambient air quality data. AQS stores data from over 10,000 monitors, 5000 of which are currently active. As discussed in more detail elsewhere, State, Local and Tribal agencies collect the data and submit it to AQS on a periodic basis.

This area is primarily intended for direct users of AQS, i.e., those in the state, local and tribal agencies and within EPA who load data into the AQS database or use data from this database for analysis.


Training - Schedule of upcoming training sessions and training materials available for downloading.

Online Training - Video Online training sessions

Contacts - Contact information for AQS and CDX help, EPA headquarters and regional staff as well as state/local/tribal representatives.

Related Links - Links to other sites that have information related to Air Quality.

AQS Tools - Download tools that compliment AQS (AQS QA Transaction Generator)

RSS Feed - AQS User Info  RSS Feed - AQS User Info

Basic Information - Brief description of the purpose of the Air Quality System.

AQS Web Application - Pathway to the AQS web application where registered users load and maintain AQS data, and retrieve reports. Release notes are also found here.

AQS Discoverer Pathway to the web version of the ad hoc query tool from Oracle Corporation. (For registered users only.)

Manuals & Guides - AQS Manuals and User Guides available for on-line browsing or downloading, including the AQS Coding Manual, Data Dictionary, Input Transaction Format, and User Guides.

Obtaining AQS Data - How to get AQS data if you are not a registered AQS user or you need detailed data for years prior to 10 years ago. There are also links to over 100 files with national data for downloading.

AQS Conferences - Information about upcoming conferences and handouts from the previous conferences. These conferences are generally held once each year.

Frequent Questions - Questions and answers about AQS, sorted by topic.

Memos - Memos and E-mails generally sent to all registered AQS users. (Release notes for the AQS Web application are found via the AQS Web Change Log page.)

User Registration - Steps to obtain an AQS User ID. Generally, only personnel from federal, state, local, or tribal agencies providing data to the EPA or analyzing that data for their agency may register.


AQS Frequent Questions | Technology Transfer Network | Air & Radiation

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